Process of mirroring glass or like surfaces.



oARLIiERMA NvoN"rio ssLE, QF RA'JSEBEU finannitnsnitii 'ror OHEMISGHE'FABRIK YONHEYDEN,YAKTIENGESELLSQHAFTL I 7 accesses v newsca t No.906, 229i and resident of Sedanstrasse 22, Radebeul,

near Dresden, Saxony, German Empire, have invented a new anduseful Improvement in theProcess of Mirroring Grlass or Like Surfaces, of which the following is a specification.

mfi by silver are based on the fact that meta ic. silver is precipitated on the surface to be mirrored from an alkaline solution of ni-' trate of silver in distilled water by means of All known processes have disar vantages and require recautions so that only the man highly sk ed in the art will be ableto manufacture faultless IIllIIOIS. Such precautions are not necessary with the process forming the object of the present invention, in as much as it is so simple that even a man-not experienced is able to manufacture mirrors by it. The de vices necessary for performing the new. mirroring-process are also far simpler. Up to the present it was-necessary, in case the mirayer or skin was damaged or destroyed, to sometimes again grind the; late to be newly mirrored. Siuch manipu ations are not necessary-with the new "process forming" the object'of. the present invention. 'Furthermore-the known reducing" rocesses show also the great disadvanta e t at thesilver solution because of alrea y containing the reducing substances, ermanently precipitate silver'and are re uced already in the" liquid-vessels; whereby the precipitated silver is only partly used for forming the mirror; whereas the silver not precipitated as a mirror must permanentl be worked up again to form nitrates of silver. It has been tried to obviate these drawbacks by separately sprinklingfia silver solution and a re- .ducing solution by means pf. two nozzles; however such process 'is' accompanied by other difficulties and is therefore not in use inpractice.

NOW I have found thatall drawbacks of the processes known up to the present can be obviated by not applying, on the surface to be silvered as formerly done, the silver-solution containin all-components'necessary for the reduction ut a'silver-solution which as.

such has no mirroring action because of either not containing the reducing substance r l Speei fication of Letters lat'enti Application filed Jul 14, 190a. Serial No. 49,600. 5

The numerous known processes of mirrorby Water.

ept apart from each other,

or the .alkaline substance for'the. reduction and by only separately causlng the as-Isa has? 3,1908;

reductionto silver in a second stage by a s eciaI action of these absent substances." So

:for instance a solution of nitrate of silver in a small quantit of water to which formalde hyde is adde will not'have a mirroring effeet." A mirror will onlybe' formed when the surfaces coated with such a solution are exosed to the action of aline re or instanceto ammonia. Or on t e other hand the solution in ammonia. of oxid of silents as ver will not have a mirroring efiect; the mir- I ror will only be formed when the 'surface' coated with such am nonia co'mlpound is exposed to the action of formalde yde vapors.

Theessential feature of the present invention consists in that the applying of the silver solution and. the reduction takes place in.two

consecutive stages, whereas, up to the prescut, the solution reducingper se was brought to its action inone proce ure.

Example: 6- parts by weight (6 grams) of nitrate of silver are dissolved in 3 parts by volume (3 cubic centimeters) of distilled water, towhicha mixture composed of 6 parts by volume (6 cubic centimeters) of a 40 .percent. solution of formaldehyde and 7 plarts'CZ- cubic centimeters) of glycerin or a 'ghly concentrated sugar solutlon, syrup or gum-solution is added. i I,

If necessary a small quantity of acetone is added to securea good adhering of the liquid I to the glass. Thesolution mentioned can be used either immediately orafter diluting it Such dilution depends upon the dlesired thickness of the layer or skinonthe ass. i s a-p lied to the plate and t e entire surface is ru bed up by means of a brush or a rubber composed of deerskin; hereafter a lar er quantity of the solution is poured on and t e surface is slanted in such a manner that the liquid mayreach all points of the surface to be mirrored. The ate is hereafter laced vertically so that t e superfluous so ution may run off. Thesolution will adhereto the First a small quantit of the solution plate in a quantity sufficient to produce a'.

good silver layer or'skin on the mirror. The superfluous 1i uid having run off the plate is ex osed to t e action ofammonla by placing t is plate within a vessel or a receptacle the bottom of which is covered with vapors: of ammonia or by directin ammonia vapors against the plateor by ipping the latter nished. The; mentionedv substances added,

crease the. adhering of the liquid to the suranother mass for instance celluloid, mica,

the formaldehyde may be'replaoed by other into a solution offammonia in benzene or another suitable ,dissolving agent which does not withtheaqueoussohitions and does not wash away the silver-so ution a lied. The mirror thus formed near y instantaneously in distinction from -the washed" for-fashort f-time, dried and varas gum arabic', glycerin etc. have only, the purpose to concentrate the liquidor to inreducing-substances, other" rea ents of alkaline action maybe iisedinstea of ammonia. The probes inayalso beefli'ected in an inverse maimer byapplying' an alkaline silversolution,ffor instance a solution ina mnonia of oxid ofsilver, to the surface and by allowing the reducing substance, for instance the vapo'rs of formaldehyde, to act'in the second stage: Besides glass, objects consisting of hardened gelatin and the like may be mirrored in the manner described.

As explained above, the thickness of the 'may be eflecte Prdcesss W 111 user The IIllIIOI is then the plate.

" be varied according to the mirror-layer'may v concentration o the solution; therefore the process described is highly suitable for the manufacture of transparent -mirrors the manufacture of which was accompanied up to the 'resentf.;by great difficulties. Of course, t e app g of, the silver-solution in-any suitable manner. An es' ecially important advantage-of the process escribed be seen in-the fact that mirrors, thelayer of which is damaged or destroyed in any way, can be coated again without necessitating a second grinding of Mirrors to be. provided with cut edges, facets for the like, were, u to the present, ground after mirroring. owthe present process also allows the subsequent mirroring of the object ground; because the silver la er-can be distributed over the en'- tire su ace and also" over the edges of the same.

. What I'clair'n is; v

The plrlocess for mirrorin glass or like surfaces w a silver salt andran 'alk e or 'areducing substance ofno mirroring quality to the surface to bemirrored and IIIPIGGlPitEttiDg the silver by a subsequent action of a reducing or alkaline substance, substantially as and for the purpose specified. I

In testimony, that I claim-the foregoing as my invention, I have presence of two witnesses, this second dayof uly, 1908.

4 CARL HERMANN-VON HOESSLE;

Witnesses:- Gnone Hnossmonngi CLAR SIMON.

ch consists in ap ymg a solution of signed my name 4n 

